阅读说明：本技术 电动汽车充电控制方法、系统及存储介质 (Electric vehicle charging control method and system and storage medium ) 是由 王业斌 王书洋 孙焕丽 许立超 王雯婷 韩金磊 于 2021-06-29 设计创作，主要内容包括：本发明公开一种电动汽车充电控制方法、系统及存储介质。电动汽车充电控制方法包括：获取电池当前温度并判断电池当前温度是否处于最优充电温度；若电池当前温度处于最优充电温度,则判断用户选择的充电模式,所述充电模式包括普通充电模式和定时充电模式；若用户选择的充电模式为定时充电模式,则通过大数据分析用户的预计用车时间及目标SOC,并判断预计用车时间及目标SOC是否满足用户需求；若不满足,则提示用户输入预计用车时间及目标SOC,并按照用户输入的预计用车时间及目标SOC进行充电；若满足,则按照大数据分析的预计用车时间及目标SOC进行充电。本发明能在满足用户对电动汽车充电需求的前提下保证充电的安全性。(The invention discloses an electric vehicle charging control method, a system and a storage medium. The electric vehicle charging control method comprises the following steps: acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature or not; if the current temperature of the battery is at the optimal charging temperature, judging a charging mode selected by a user, wherein the charging mode comprises a common charging mode and a timing charging mode; if the charging mode selected by the user is the timing charging mode, analyzing the estimated vehicle using time and the target SOC of the user through big data, and judging whether the estimated vehicle using time and the target SOC meet the requirements of the user; if not, prompting the user to input the predicted vehicle using time and the target SOC, and charging according to the predicted vehicle using time and the target SOC input by the user; and if so, charging according to the estimated vehicle-using time and the target SOC analyzed by the big data. The invention can ensure the charging safety on the premise of meeting the charging requirement of the user on the electric automobile.)

1. The electric vehicle charging control method is characterized by comprising the following steps:

A. acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature or not;

B. if the current temperature of the battery is at the optimal charging temperature, judging a charging mode selected by a user, wherein the charging mode comprises a common charging mode and a timing charging mode;

C. if the charging mode selected by the user is the timing charging mode, analyzing the estimated vehicle using time and the target SOC of the user through big data, and judging whether the estimated vehicle using time and the target SOC meet the requirements of the user;

D. if not, prompting the user to input the predicted vehicle using time and the target SOC, and charging according to the predicted vehicle using time and the target SOC input by the user;

E. and if so, charging according to the estimated vehicle-using time and the target SOC analyzed by the big data.

2. The electric vehicle charging control method according to claim 1, wherein the step B further comprises:

and B1, if the current temperature of the battery is not at the optimal charging temperature, controlling the temperature of the battery to reach the optimal charging temperature, and then entering the judgment of the charging mode.

3. The electric vehicle charging control method according to claim 1, wherein in the step a, the optimal charging temperature is calculated and obtained based on big data analysis.

4. The electric vehicle charging control method according to claim 1, further comprising, after the step E, the steps of:

s1, detecting whether the user selects an emergency charging mode;

s2, if the user selects the emergency charging mode, judging whether the SOH of the current battery is in a safe range;

s3, if the SOH of the current battery is in the safety range, prompting the user to input the expected charging time;

s4, calculating a target SOC according to the predicted charging time input by the user;

and S5, detecting whether the target SOC meets the user requirement, and if so, charging according to the predicted charging time input by the user.

5. The electric vehicle charging control method according to claim 4, wherein the step S5 further includes:

s51, if the target SOC does not meet the user requirement, prompting the user to input the target SOC;

s52, judging whether the target SOC input by the user has safety risk in the predicted charging time input by the user;

and S53, if the safety risk exists, prompting the user, and providing a limit target SOC for the user to select.

6. The electric vehicle charging control method according to claim 4, wherein the step S2 further includes:

and S21, judging whether the current temperature of the battery is at the optimal charging temperature, and if not, controlling the temperature of the battery to reach the optimal charging temperature.

7. The electric vehicle charging control method according to claim 4, wherein the step S3 further includes:

and S31, if the SOH of the current battery is not in the safety range, calling the emergency charging map to limit the charging current.

8. An electric vehicle charging control system, comprising:

the temperature judging module is used for acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature;

the charging mode judging module is used for judging a charging mode selected by a user when the current temperature of the battery is at the optimal charging temperature, and the charging mode comprises a common charging mode and a timing charging mode;

the analysis module is used for analyzing the estimated vehicle using time and the target SOC of the user through big data and recommending the estimated vehicle using time and the target SOC to the user when the charging mode selected by the user is a timing charging mode;

the detection module is used for detecting whether a user inputs the predicted vehicle using time and the target SOC;

and the charging execution module is used for charging according to the predicted vehicle using time and the target SOC input by the user when detecting that the predicted vehicle using time and the target SOC are input by the user, and charging according to the predicted vehicle using time and the target SOC recommended to the user when detecting that the predicted vehicle using time and the target SOC are not input by the user.

9. An electric vehicle charging control system, comprising:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement the electric vehicle charging control method of any of claims 1-7.

10. A computer-readable storage medium, on which a computer program is stored, wherein the program, when executed by a processor, implements the electric vehicle charging control method according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of electric vehicle charging, in particular to a method and a system for controlling electric vehicle charging and a storage medium.

Background

At present, the number of electric automobiles is continuously increased, and the charging safety requirement of a charging system of the electric automobiles is higher. If the charging time of the electric automobile is longer or the battery is charged all the time after being fully charged, safety accidents are easy to happen. After the battery is fully charged, the battery is continuously charged, that is, the battery is overcharged, which may cause the conditions of battery internal pressure rise, battery deformation, liquid leakage and the like to occur, so that the performance of the battery is remarkably reduced, and even the battery is damaged.

Therefore, it is desirable to provide a method, a system and a storage medium for controlling charging of an electric vehicle to solve the above problems.

Disclosure of Invention

In order to solve the technical problems, the invention provides an electric vehicle charging control method, a system and a storage medium, which can ensure the charging safety on the premise of meeting the charging requirement of a user on an electric vehicle.

The invention adopts the following technical scheme:

a charging control method for an electric automobile comprises the following steps:

A. acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature or not;

B. if the current temperature of the battery is at the optimal charging temperature, judging a charging mode selected by a user, wherein the charging mode comprises a common charging mode and a timing charging mode;

C. if the charging mode selected by the user is the timing charging mode, analyzing the estimated vehicle using time and the target SOC of the user through big data, and judging whether the estimated vehicle using time and the target SOC meet the requirements of the user;

D. if not, prompting the user to input the predicted vehicle using time and the target SOC, and charging according to the predicted vehicle using time and the target SOC input by the user;

E. and if so, charging according to the estimated vehicle-using time and the target SOC analyzed by the big data.

As an alternative to the above-mentioned electric vehicle charging control method, the step B further includes:

and B1, if the current temperature of the battery is not at the optimal charging temperature, controlling the temperature of the battery to reach the optimal charging temperature, and then entering the judgment of the charging mode.

As an alternative to the above electric vehicle charging control method, in step a, the optimal charging temperature is calculated and obtained based on big data analysis.

As an alternative to the above-mentioned electric vehicle charging control method, the step E is followed by the step of:

s1, detecting whether the user selects an emergency charging mode;

s2, if the user selects the emergency charging mode, judging whether the SOH of the current battery is in a safe range;

s3, if the SOH of the current battery is in the safety range, prompting the user to input the expected charging time;

s4, calculating a target SOC according to the predicted charging time input by the user;

and S5, detecting whether the target SOC meets the user requirement, and if so, charging according to the predicted charging time input by the user.

As an alternative to the above-mentioned electric vehicle charging control method, the step S5 further includes:

s51, if the target SOC does not meet the user requirement, prompting the user to input the target SOC;

s52, judging whether the target SOC input by the user has safety risk in the predicted charging time input by the user;

and S53, if the safety risk exists, prompting the user, and providing a limit target SOC for the user to select.

As an alternative to the above-mentioned electric vehicle charging control method, the step S2 further includes:

and S21, judging whether the current temperature of the battery is at the optimal charging temperature, and if not, controlling the temperature of the battery to reach the optimal charging temperature.

As an alternative to the above-mentioned electric vehicle charging control method, the step S3 further includes:

and S31, if the SOH of the current battery is not in the safety range, calling the emergency charging map to limit the charging current.

An electric vehicle charging control system comprising:

the temperature judging module is used for acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature;

the charging mode judging module is used for judging a charging mode selected by a user when the current temperature of the battery is at the optimal charging temperature, and the charging mode comprises a common charging mode and a timing charging mode;

the analysis module is used for analyzing the estimated vehicle using time and the target SOC of the user through big data and recommending the estimated vehicle using time and the target SOC to the user when the charging mode selected by the user is a timing charging mode;

the detection module is used for detecting whether a user inputs the predicted vehicle using time and the target SOC;

and the charging execution module is used for charging according to the predicted vehicle using time and the target SOC input by the user when detecting that the predicted vehicle using time and the target SOC are input by the user, and charging according to the predicted vehicle using time and the target SOC recommended to the user when detecting that the predicted vehicle using time and the target SOC are not input by the user.

An electric vehicle charging control system comprising:

one or more processors;

a memory for storing one or more programs;

when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the electric vehicle charging control method as described above.

A computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements the electric vehicle charging control method as described above.

The invention has the advantages that: judging the temperature of the battery before charging, and charging the battery when the temperature of the battery is at the optimal charging temperature; providing a plurality of charging modes for a user to select, so that the user can reasonably select the charging modes according to the self requirement, and the charging modes can be switched; when the user selects the timing charging mode, the expected vehicle using time and the target SOC (State Of Charge) Of the user are analyzed through the big data and recommended to the user, the big data analysis can be carried out according to the habit Of the user to use the vehicle at ordinary times, the user can directly select the expected vehicle using time and the target SOC which are analyzed by the system, and the method is more convenient and faster; when the estimated vehicle using time and the target SOC of the big data analysis do not meet the requirements of the user, the user can also set the estimated vehicle using time and the target SOC by himself; the charging is carried out according to the estimated vehicle using time of the user and the target SOC, the charging starting time is reasonably planned, and the electric vehicle is not always charged, so that the charging amount can reach the electric quantity required by the user when the user uses the vehicle, the overcharging can be prevented, and the safety in the charging process is ensured.

Drawings

FIG. 1 is a block flow diagram illustrating an embodiment of a method for controlling charging of an electric vehicle according to the present invention;

FIG. 2 is a block diagram illustrating a charging control method for an electric vehicle according to another embodiment of the present invention;

fig. 3 is a flowchart of an electric vehicle charging control method according to another embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.

First, an application scenario of the present invention is explained, and with the increase of electric vehicles, charging piles are also visible everywhere, for example, parking lots in shopping malls or other places are all provided with charging piles. The description is given here by way of example in the marketplace. When the user drives to places such as market, go shopping before charging electric automobile even connecting to fill electric pile and having left promptly. Sometimes, shopping time is long, the electric automobile does not need to be charged for that long time, the electric automobile is charged fully before a user takes the electric automobile from a charging place, and the battery is always in a charging state until the user takes the electric automobile, so that potential safety hazards exist. Therefore, the invention provides a charging control method for an electric vehicle, which can ensure the charging safety on the premise of meeting the charging requirement of a user on the electric vehicle. In other words, the electric quantity required by the user can be ensured before the user leaves the market, and the battery overcharge can be avoided.

Example one

The embodiment of the invention provides a charging control method for an electric automobile. As shown in fig. 1, the control method includes the steps of:

s100, acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature.

Specifically, after the user is connected electric automobile with fill electric pile, whether the battery that detects electric automobile at first is in the optimum charging temperature, and the optimum charging temperature can be calculated and is acquireed based on big data analysis, just charges the battery when the battery is in the optimum charging temperature to guarantee the security of charging, avoid the battery to charge under the high temperature condition. The optimum charging temperature may be a temperature interval in which the battery is judged to be at the optimum charging temperature when the current temperature of the battery is within the temperature interval.

S200, if the current temperature of the battery is at the optimal charging temperature, judging a charging mode selected by a user, wherein the charging mode comprises a common charging mode and a timing charging mode.

Specifically, in the present invention, a plurality of charging modes are provided for the user to select, such as a normal charging mode and a timed charging mode. The user can select and switch the charging mode on a mobile terminal, such as a mobile phone app, a vehicle T-box terminal, a smart car key, and the like. The ordinary charging mode is a general charging mode, namely charging is started after the charging pile is connected. The timing charging mode is an intelligent charging mode, can intelligently plan the time for starting charging according to the vehicle using time of a user and the target SOC, is a delayed charging mode, can reduce the time interval between the charging termination time and the vehicle using time of the user, and improves the safety of battery charging. The car using time is the car taking time of the user, or the time when the user drives to leave the shopping mall. The target SOC is the target battery level that the user wishes to reach.

And S300, if the charging mode selected by the user is the timing charging mode, analyzing the estimated vehicle using time and the target SOC of the user through big data, and judging whether the estimated vehicle using time and the target SOC meet the requirements of the user.

Specifically, when the user selects the timed charging mode, the estimated vehicle-use time and the target SOC of the user can be analyzed through big data. The time a user may leave a mall is analyzed, for example, by the time the user has gone to and left the mall. After the estimated vehicle-using time and the target SOC are analyzed through the big data, whether the estimated vehicle-using time and the target SOC meet the user requirements or not is judged, and the judgment mode can be, for example, displaying the analyzed estimated vehicle-using time and the analyzed target SOC to a user, and judging whether the user requirements are met or not through a mode of clicking confirmation by the user. The big data analysis means that analysis and calculation are carried out according to user charging data so as to obtain the optimal temperature of the battery during initial charging of a user, the expected vehicle using time of the user, the target SOC and the like. The user charging data comprises data such as a user charging place, a charging starting time, a vehicle using time and a battery charging initial temperature.

And S400, if the estimated vehicle-using time does not meet the preset target SOC, prompting the user to input the estimated vehicle-using time and the target SOC, and charging according to the estimated vehicle-using time and the target SOC input by the user.

And S500, if the maximum vehicle speed is met, charging is carried out according to the estimated vehicle using time and the target SOC which are analyzed by the big data.

Specifically, when the estimated vehicle-using time and the target SOC which are analyzed through the big data meet the user requirements, the vehicle-using time and the target SOC which are analyzed are directly charged. And if the estimated vehicle using time and the target SOC which are analyzed through the big data do not meet the requirements of the user, prompting the user to manually input the estimated vehicle using time and the target SOC, and then charging according to the estimated vehicle using time and the target SOC input by the user.

Fig. 2 is a block flow diagram of another embodiment of the electric vehicle charging control method according to the present invention, and referring to fig. 2, step S200 further includes:

and S210, if the current temperature of the battery is not at the optimal charging temperature, controlling the temperature of the battery to reach the optimal charging temperature, and then judging a charging mode.

Specifically, when the current temperature of the battery is not at the optimal charging temperature, there is a potential safety hazard if the battery is directly charged, and therefore, the battery needs to be cooled, for example, the temperature of the battery is controlled by a thermal management temperature control unit, so that the battery reaches the optimal charging temperature calculated by big data analysis.

Referring to fig. 3, the step S500 is followed by the steps of:

s610, detecting whether the user selects an emergency charging mode;

s620, if the user selects the emergency charging mode, judging whether the SOH of the current battery is in a safe range;

s630, if the SOH of the current battery is within the safety range, prompting a user to input the expected charging time;

s640, calculating a target SOC according to the predicted charging time input by the user;

and S650, detecting whether the target SOC meets the user requirement, and if so, charging according to the predicted charging time input by the user.

Specifically, the invention also provides an emergency charging mode for the user to select, for example, after the user selects the ordinary charging mode or the timing charging mode, if the user needs to go home in advance when the user needs to take an emergency vehicle, such as shopping, the user can switch to the emergency charging mode to realize quick charging, so that the user can take the vehicle in advance.

Therefore, in the invention, whether the user selects the emergency charging mode or not is detected in real time in the process of charging the electric automobile, so that the electric automobile can be charged according to the emergency charging mode. As shown in fig. 3, the emergency charging mode needs to determine the SOH (State Of Health) Of the current battery, and the subsequent emergency charging mode can be continued only when the SOH Of the current battery is within a safe range. After the SOH of the current battery is judged to be in the safety range, the user is required to input the predicted charging time, and the intelligent charging system calculates the target SOC after the predicted charging time. And if the target SOC meets the requirements of the user, executing a subsequent charging process, and charging according to the predicted charging time input by the user.

Step S650 further includes:

s651, if the target SOC does not meet the requirements of the user, prompting the user to input the target SOC;

s652, judging whether a target SOC input by a user has a safety risk within the expected charging time input by the user;

and S653, if the safety risk exists, prompting the user, and providing a limit target SOC for the user to select.

Specifically, in step S650, if the target SOC calculated according to the estimated charging time input by the user does not meet the target SOC required by the user, the user is required to provide the target SOC, the charging system determines whether the target SOC has a safety risk within the estimated charging time, and if there is no safety risk, a subsequent charging process may be executed; if the target SOC has the safety risk, prompting the user that the target SOC has the potential safety hazard, and providing a target SOC safety boundary (namely a limit target SOC) for the user to select so as to execute a subsequent charging process.

Step S620 further includes:

and S621, judging whether the current temperature of the battery is at the optimal charging temperature, and if not, controlling the temperature of the battery to reach the optimal charging temperature.

Specifically, in step S620, when the user selects the emergency charging mode, before the charging process is executed, it is further required to determine whether the current temperature of the battery is at the optimal charging temperature, and if the current temperature of the battery is at the optimal charging temperature, the charging process is executed; and if the current temperature of the battery is not at the optimal charging temperature, controlling the temperature of the battery to reach the optimal charging temperature, and executing a charging process.

Step S630 further includes:

and S631, if the SOH of the current battery is not in the safety range, calling the emergency charging map to limit the charging current.

Specifically, after the SOH of the present battery is detected in S620, in step S630, if the SOH of the present battery is not within the safety range, the emergency charging map is called to limit the charging current. The emergency charging map is an emergency charging ammeter preset in the system. Since the SOH of the current battery is no longer within the safety range, the charging current needs to be limited by the emergency charging map during the charging process, so as to ensure the safety of the charging process.

Example two

Based on the electric vehicle charging control method, the second embodiment of the invention also provides an electric vehicle charging control system. The electric automobile charge control system includes:

the temperature judging module is used for acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature; the specific example is as described in the first embodiment.

The charging mode judging module is used for judging a charging mode selected by a user when the current temperature of the battery is at the optimal charging temperature, and the charging mode comprises a common charging mode and a timing charging mode; the specific example is as described in the first embodiment.

The analysis module is used for analyzing the estimated vehicle using time and the target SOC of the user through big data and recommending the estimated vehicle using time and the target SOC to the user when the charging mode selected by the user is a timing charging mode; the specific example is as described in the first embodiment.

The detection module is used for detecting whether a user inputs the predicted vehicle using time and the target SOC; the specific example is as described in the first embodiment.

The charging execution module is used for charging according to the predicted vehicle using time and the target SOC input by the user when the fact that the predicted vehicle using time and the target SOC are input by the user is detected, and charging according to the predicted vehicle using time and the target SOC recommended to the user if the fact that the predicted vehicle using time and the target SOC are not input by the user is detected; the specific example is as described in the first embodiment.

EXAMPLE III

The third embodiment of the invention also provides another electric vehicle charging control system. The electric automobile charge control system includes:

the system comprises an identification unit, a big data calculation unit, a thermal management temperature control unit and a charging execution unit.

The identification unit may be used to identify the current battery SOC and the battery temperature.

And the big data calculation unit performs analysis and calculation according to the user charging data to obtain the optimal temperature of the battery during initial charging of the user, the estimated vehicle using time of the user, the target SOC and the like. The user charging data comprises data such as a user charging place, a charging starting time, a vehicle using time and a battery charging initial temperature.

The thermal management temperature control unit is used for adjusting the battery temperature to the optimal charging temperature calculated by the big data analysis when the initial charging temperature of the battery is not at the optimal charging temperature.

The charging execution unit is used for executing a charging process according to the charging mode.

Example four

Based on the electric vehicle charging control method, the fourth embodiment of the invention also provides another electric vehicle charging control system. The electric vehicle charging control system includes but is not limited to: one or more processors and memory.

The memory is a computer-readable storage medium, and can be used for storing software programs, computer-executable programs, and modules, such as program instructions corresponding to the electric vehicle charging control method in the embodiment of the present invention. The processor executes various functional applications and data processing of the vehicle by running software programs, instructions and modules stored in the memory, so that the electric vehicle charging control method is realized.

The memory can mainly comprise a program storage area and a data storage area, wherein the program storage area can store an operating system and an application program required by at least one function; the storage data area may store data created according to the use of the terminal, and the like. Further, the memory may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device.

EXAMPLE five

An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements a method for controlling charging of an electric vehicle, and the method for controlling charging of an electric vehicle includes the following steps:

s100, acquiring the current temperature of the battery and judging whether the current temperature of the battery is at the optimal charging temperature or not;

s200, if the current temperature of the battery is at the optimal charging temperature, judging a charging mode selected by a user, wherein the charging mode comprises a common charging mode and a timing charging mode;

s300, if the charging mode selected by the user is the timing charging mode, analyzing the predicted vehicle using time and the target SOC of the user through big data, and judging whether the predicted vehicle using time and the target SOC meet the requirements of the user;

s400, if the estimated vehicle-using time does not meet the preset target SOC value, prompting a user to input the estimated vehicle-using time and the target SOC, and charging according to the estimated vehicle-using time and the target SOC input by the user;

and S500, if the maximum vehicle speed is met, charging is carried out according to the estimated vehicle using time and the target SOC which are analyzed by the big data.

Of course, the computer-readable storage medium provided by the embodiments of the present invention has computer-executable instructions that are not limited to the operations of the method described above, and may also perform related operations in the electric vehicle charging control method provided by any embodiment of the present invention.

Those of ordinary skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the invention are all or partially effected when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on or transmitted over a computer-readable storage medium. The computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The available media may be magnetic media (e.g., floppy disks, hard disks, tapes), optical media (e.g., DVDs), or semiconductor media (e.g., Solid State Disks (SSDs)), among others.

In the above embodiment, each included unit and module is only divided according to functional logic, but is not limited to the above division as long as the corresponding function can be realized; in addition, specific names of the functional units are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present invention.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.